Kidney contains renin and kallikrein bound to membranes. The enzymes are present in a plasma membrane enriched fraction obtained after differential centrifugation of the homogenized kidney cortex. The endoplasmic reticulum enriched fraction, however, also contains both enzymic activities. We will isolate the membranes the enzymes are bound to and establish the characteristics of the enzymes released from the membranes. We will study the process of activation and solubilization of renin and kallikrein and the various stimuli that lead to the release of the hypotensive and hypertensive enzymes.